1. Field of the Invention
The present invention relates to a photosensitive transfer material, a pattern forming method, and an etching method.
2. Description of the Related Art
In organic EL display devices, liquid crystal display apparatuses, capacitance-type input devices, and the like, a pattern-formed interlayer insulating film is provided. In order to form the interlayer insulating film, a method is widely used in which the number of steps necessary to obtain a required pattern shape is small and, furthermore, from the viewpoint that sufficient flatness is obtainable, a photosensitive resin composition layer transferred onto an arbitrary substrate using a photosensitive transfer material is exposed through a mask having a desired pattern, is partially cured, and then is developed.
On the basis of the difference in the photosensitive system, photosensitive resin compositions are classified into negative photosensitive resin compositions which remain as images when irradiated with an active light ray and positive photosensitive resin compositions which remain as images when not irradiated with an active light ray. In the case of the negative resin compositions, since exposed portions are cured, it is necessary to dispose of individual substrates when the obtained pattern shape is poor. On the other hand, in the case of the positive resin compositions, since the solubility of exposed portions is increased using a photosensitizer that generates an acid when irradiated with an active light ray, both exposed portions and non-exposed portions are not cured during pattern exposure and, when the obtained pattern shape is poor, substrates is reusable (reworkable) through full-surface exposure or the like. Therefore, from the viewpoint of so-called excellent reworkability, the positive photosensitive resin compositions are preferably used.
As examples of the transfer material in which the above-described positive photosensitive resin composition is used, transfer materials described in JP4544219B, JP4654938B, and JP2010-211109A are known.
JP4544219B describes a transfer film including a support film and a resin film formed of a radiation-sensitive positive-tone resin composition on the support film. In this document, as the radiation-sensitive positive-tone resin composition, a chemical amplification-type radiation-sensitive positive-tone resin composition including a polymer having a structural unit that includes an acid-dissociable functional group which is disassociated by an acid and generates an acidic functional group, a radiation-sensitive acid generator, and an organic solvent is described. The document describes that, when the radiation-sensitive positive-tone resin composition is used as a dry film resist for plate patterning, sensitivity, resolving properties, and the like are excellent, adhesion to substrates is excellent, residue is not generated in opening portions after development, the occurrence of cracking of the resin film after plating can be suppressed, plates being pressed into the resin film can be suppressed, the dimensional change in patterns formed in response to a change in the exposure intensity is small, and the generation of T-top by amines present in the environment can be solved.
JP4544219B describes that the resin film in the transfer film can be used with a thickness in a range of 5 μm to 200 μm.
JP4654938B describes a method in which a resist pattern is formed using a photosensitive element formed by applying a chemical amplification-type positive photosensitive resin composition onto a support. JP4654938B describes a chemical amplification-type positive photosensitive resin composition including a thermopolymerizing compound having a bond that is cut by an acid and two or more ethylenic unsaturated bonds in the molecule, a thermopolymerization initiator that initiates a thermopolymerization reaction of the thermopolymerizing compound, and a compound that generates an acid when irradiated with an active energy ray. This document discloses a positive photosensitive resin composition in which a thermopolymerizing compound having an —O—C—O— portion is used. However, the thermopolymerizing compound described in JP4654938B is not a polymer and the document describes only polymerizing compounds (monomers). Since Paragraph 0021 in JP4654938B describes that the —O—C—O— portion in the thermopolymerizing compound is cut by an acid and is thus decomposed into an —OH group and a ketone compound, and the formation of this —OH group makes the thermopolymerizing compound soluble in an alkaline aqueous solution, the —O—C—O— portion in the thermopolymerizing compound does not protect an acidic group. In addition, since a cured film after exposure is developed using methanol in examples of JP4654938B, there is no study described in JP4654938B regarding the use of a thermopolymerizing compound having an acidic group in order to improve developing properties using an alkaline aqueous solution.
JP2010-211109A describes that, by using a manufacturing method of a resin pattern including a step of applying a positive photosensitive resin composition to a film base material and then removing a solvent, thereby producing a photosensitive dry film, a step of pressing the photosensitive dry film onto a pattern-disposed substrate, thereby forming a photosensitive layer, a step of irradiating the photosensitive layer with an active light ray through a mask, a step of developing the photosensitive layer using an alkaline aqueous solution, a step of rinsing the photosensitive layer using at least one solvent selected from the group consisting of water and acidic aqueous solutions, a step of irradiating the entire photosensitive layer with an active light ray, and a step of curing the photosensitive layer at a temperature in a range of 100° C. to 400° C., the warpage of FPC obtained after a baking step is reduced and mechanical properties are improved, whereby solvent resistance can be improved. In the chemical amplification-type positive dry film of JP2010-211109A, a polyimide resin is used as an alkali-soluble resin and a naphthoquinone diazide compound is combined with the polyimide resin as a photosensitizer that generates an acid when irradiated with an active light ray, but there is no description regarding an aspect in which the alkali-soluble resin has a crosslinking group or a protected group of an acid group.